In source and drain regions of conventional transistor, semiconductor and metal electrode directly contact with each other, resulting in high contact resistance and high Schottky barrier and thereby affecting device performance. Nickel (Ni) and silicon (Si) can react to form NiSi silicide as contact material, greatly reducing contact resistance and Schottky barrier and enjoying wide use. At present, NiSi has been used as contact material for source and drain of metal-oxide-semiconductor field-effect transistor (MOSFET) manufactured by Intel, AMD and so on.
With the development of semiconductor technology, SiGe, a kind of novel high-mobility material, is an ideal substitute for Si material in the future. However, during the reaction between Ni and SiGe to produce silicide, the presence of germanium (Ge) atoms is likely to cause different reaction sequence of Ni with Si and Ge atoms, making it difficult to form continuous NiSiGe thin film. Moreover, the diffusion of Ge can cause poor electrical performance of the formed NiSiGe thin film, affecting NiSiGe thin film as source and drain contact to a great extent.
Therefore, the present invention will provide a new method of NiSiGe growth using an aluminum (Al) interlayer to prevent the diffusion of Ge atoms, thereby forming epitaxial NiSiGe thin film of high quality.